The number of devices connected in a network continues to expand. With this expansion, management of the devices, both connected nodes and the switches forming the fabric becomes more difficult.
The Fibre Channel (FC) protocol is a switched communications protocol that allows concurrent communication among servers, workstations, storage devices, peripherals, and other computing devices. Fibre Channel can be considered a channel-network hybrid, containing enough network features to provide the needed connectivity, distance and protocol multiplexing, and enough channel features to retain simplicity, repeatable performance and reliable delivery. Fibre Channel is capable of full-duplex transmission of frames at rates currently extending from 1 Gbps (Gigabits per second) to 10 Gbps or more. It is also able to transport commands and data according to existing protocols, most commonly Small Computer System Interface (SCSI) in the form of FCP.
In a typical usage, Fibre Channel is used to connect one or more computers or workstations together with one or more storage devices. In the language of Fibre Channel, each of these devices is considered a node. One node can be connected directly to another, or can be interconnected such as by means of a Fibre Channel fabric. The fabric can be a single Fibre Channel switch, or a group of switches acting together. Technically, the N_port (node ports) on each node are connected to F_ports (fabric ports) on the switch. Multiple Fibre Channel switches can be combined into a single fabric. The switches connect to each other via E_Port (Expansion Port) forming an interswitch link, or ISL. The fabric can be divided or arranged both physically and virtually into one or more groupings, with each grouping operating according to its own rules, protocols, permissions, etc.
Network management devices are used to monitor status of the various network devices and to perform configuration options. In many instances the network management device is a workstation connected to the network devices and running management software. The management software communicates with the various devices, stores relevant information, such as various device parameters and statistics, and provides a user interface, usually a graphical user interface (GUI) for ease of use by the system administrators. Using the GUI the administrator can easily determine network topology, status on the devices and links in the network and change device configuration. To obtain the network device information the management software polls each network device periodically and requests the desired information, which is then stored and any updates made to the GUI.
As the fabric grows larger and is divided into more and more groupings of various types, the total parameters used to define interconnections, security settings, etc. become large, making management of the network more complicated. As the number of devices is growing, polling is reaching its limits. The number of transactions needed to keep the management device current becomes prohibitively expensive in terms of time and bandwidth. What is needed is a technique that allows a management device to be current on the status of devices in the network without the overheads associated with polling the devices to obtain all information.